It is possible to stain the colony bifidobacteria so that after pour plating, counting of colony will be able to be visualize as the medium will be opaque? if so, what substance can be used?? MRS media with addition of milk(opaque) will be used and cannot be serial diluted.

From wikipedia:Based on the growth profiles under different O2 concentrations, the Bifidobacterium species were classified into four classes: O2-hypersensitive, O2-sensitive, O2-tolerant, and microaerophilic. The primary factor responsible for aerobic growth inhibition is proposed to be the production of H2O2 in the growth medium. A H2O2-forming NADH oxidase was purified from O2-sensitive Bifidobacterium bifidum and was identified as a b-type dihydroorotate dehydrogenase. The kinetic parameters suggested that the enzyme could be involved in H2O2 production in highly aerated environments.[3

Forgive me because I am not entirely knowledgeable in this field, but will it work if you use horseradish peroxidase as the growth indicator, as it gives color when oxidized by hydrogen peroxide? You can also use an oxidase test: http://en.wikipedia.org/wiki/Oxidase_test.